Electric switchgear



Oct. 22, 1940. ROSSMAN ELECTRIC SWITCHGEAR Filed Dec. 28, 1936 ll Sheets-Sheet 2 Q INVENTOR. AHen M. Eossman ATTORNEY.

Oct. 22, 1940. A. M. ROSSMAN 2,218,555

ELECTRIC SWITCHGEAR Filed Dec. 28, 1956 ll Sheets-Shest I73 T F' 6 I 79 I 70 L/ WWWWWWMMWQ I 50 INVENTOR.

Allen M. [2055mm I BY' ATTORNEY.

K Oct. 22, 1940. A. M. FQOSSMAN 2,218,555 in ELECTRIC SWIT CHGEAR Filed Dec. 28, 1936 I ll Sheets-Sheet 5 503 ji jlqsjp/soa INVENTOR AHen M. Rossman ATTORNEY.

Oct. 22, 1940.

A. M. ROSSMAN ELECTRIC SWITCI'IGEAR Filed ,Dec. 28, 1936 11 Sheets-Sheet 6 k wi, 214

INVENTOR.

Allen M. Qossman ATTORNEY.

Oct. 22, 1940. A. M. ROSSMAN ELECTRIC SWITCHGEAR Filed Dec. 28, 1936 ll Sheets-Sheet 7 Mum Oct. 22, 1940. A. M. ROSSMAN ELECTRIC SWITCHGEAR 11 Sheets-Shet 10 Filed Dec. 28, 1936 Fig.2.9

I N VENTOR.

Allen M [2055 man nicmv ATTORNEY. ,6

22,1940 A. M5ROSSMAN 2,216,555

ELECTRIC SWITCHGEAR Filed Dec. 28, 1936 ll Sheets-Sheet ll Evm A l. gmw

lNVENT OR. Allen M. Qossman ATTORNEY.

Patented Oct. 22, 1940 'UNITED STATES PATENT OFFICE Misses memo swrrcnoasa Allen M. lie-man, Wilmette, 111. Application December as, me, Serial No. 111521 2: Claims. (01. 175-298) This. application is a continuation in part of my pending application, Serial No. 97.541, iiled August 24, 1936.

This invention relatesto electric switchgear, and more particularly switchgear for use on medium voltages, and medium current systems, such as metal clad switchgear, although not limited to switchgear of the metal clad type.

The switchgear of the present invention is of the horizontal drawout type adapted primarily, although not exclusively, to accommodate triple pole oil circuit breakers of the type having three poles in one tank, as disclosed in my pending application above referred to. In current practice, oil circuit breakers of the above type have a maximum operating voltage rating of approximately 15 k. v. and a maximum interrupting capacity rating of approximately 500,000 1:. v. a. It is a principal object of the present invention to provide a switchgear construction which will be more economical of construction without sacrificing safety or other desirable features of the metal clad type of switchgear. It isa fur- .ther oblect of the present invention to provide such a'switchgear wherein the various parts are more readily accessible than in the present standard construction.

Switchgear of the type with which the present invention is concerned generally, but not invariably, consist of a plurality of cells which 'are placed side by side, the number of cells being determined by the type and capacity of circuit or station involved. Each cell includes a lower compartment for receiving a circuit breaker, and an upper compartment ior'the bus-bars, the cells being located. in alignment so that the bus-bar v compartments of the respective cells form one continuous trough, with or without barriers between the cells, and through which trough the bus-bars extend longitudinally. The usual arrangement is such that the movement of the circuit breaker into proper position within the circuit breaker compartment establishes proper circuit connections to the circuit breaker. In the usual construction, that is, of the vertical-lift type of switchgear, the poles of the circuit breaker extend vertically upward and terminate in circuit breaker disconnecting contacts. These contacts cooperate with contacts carried by the lower wall of the bus-bar compartment, the arrangement being such that engagement between the cooperating disconnect contacts is made by the upward movement of the circuit breaker into position. Such arrangement necessarily precludes the possibility of access to the bus-bar compartment from the bottom thereof for repair, inspection or other purposes. I have invented a switchgear using a horizontally movable type of breaker, the construction being such that the connections are made with the circuit breaker in such a manner as to leave the bottom wall of the bus-bar compartment comparatively free so that it may be easily removed for access to the bus compartment from below, for inspection or other purposes.

It is a further object of the present invention to eliminate the necessity for insulating the busbars and other current carrying parts in the busbar compartment. In structures employing vertically movable circuit breakers, the center to center distances between the circuit breaker disconnects on the stationary structure are necessarily the same as the corresponding distances between the poles of the breaker. The circuit breakers are so compactly constructed that this distance is less than the minimum safe distance for bare conductors. The conductors from the stationary disconnects to the bus-bars must. therefore, be insulated. In view of the fact that the present switchgear utilizes the horizontally movable circuit breaker principle, rather than the vertical, the spacing between the disconnecting devices in the stationary structure may be increased over the pole spacings of the circuit breaker without interfering with the disconnecting function. Since there is more available space in the stationary structure than in the circuit breaker, I increase the spacing between the busbars and between the bus-bar leads, and I thus obviate the need for enclosing the bus-bars and the connections between them and the disconnects in insulation.

It is a further object of the present invention to eliminate the need for close tolerances in fabrication and assembly. This is accomplished by providing for relative aligning movement between certain engagi parts on the movable and on the stationary structures, and by providing means for guiding the movable contact members into proper registration with the stationary contact members even though the movable structure is considerably out of alignment with the stationary structure. Yielding means, such as springs, are provided for maintaining the relatively movable parts in proper position when they are free of one another while permitting relative motion between them to bring them into alignment in the event that the center of the movable switch member does not coincide or register with the center of the cooperating stationary switch member when they approach one another.

It is a still further object of the present invention to provide a switchgear with means whereby circuit breakers of different designs may be used with a given switchgear structure, without requiring extensive alterations. I accomplish this result by providing a movable structure in the cell of the switching unit, which movable struc ture is adapted to receive and support the oil circuit breaker. The movable structure includes the circuit breaker disconnect contacts that are movable into and out of engagement with registering contacts carried by the stationary structure. The circuit breaker is rigidly bolted in the movable structure, and suitable short leads connect the poles of the circuit breaker with the switch contacts carried by the movable structure. By this arrangement one circuit breaker may be replaced by another of different con struction even though the spacing or location of the external poles or bushings of the two circuit breakers are difl'erent. The prior constructions wherein replacement could only be had by a circuit breaker of a construction substantially the 'same as the breaker replaced, put a considerable limitation upon the flexibility of the unit. Where new units or cells were to be added to an old system, it was necessary that the new units be of the same construction as the old, or separate spare circuit breakers had to be provided. By the present arrangement, the alignment between the movable structure and the stationary structure is independent oi the alignment of the oil circuit breaker in the movable structure and independent of the positions of the bushings of the circuit breakers. It is thus possible to house any one of several diflerent designs of oil. circuit breaker in one movable structure.

It is a still further object of the present invention to provide a switchgear of the above character with an improved interlocking arrangement so that the breaker cannot be moved into or out of its operative position unless the breaker has been operated to its open circuit position. a

It is a still further object of the present invention to provide improved venting means for the escape of gases produced during operation f he circuit breaker. I provide a common manifnid for receiving the gases from each of the circuit breakers of a plurality of adjacent cells, he arran ement being such that the" circuit reakerwithin any cell may be connected to the manifold, and cannot be moved out of its cell unless and until it is disconnected from the manifold.

It is a still further object of the present invention to provide an improved disconnect switch that is particularly adaptable for use to establish connections between a movable and a stationary structure, although not limited thereto,

and characterized in that a proper contact is established between the stationary and the movable contacts of the switch even though the two are appreciably out of. alignment.

It is a still further object of the present invention to provide an improved disconnect switch v for use in establishing connections between busbars and other parts of the switching system, which switch may be mounted in the switchgear in such a manner as to afford ready access for operation and permit ready access into the bus compartment.

It is a still further object of the present inaa asss vention to provide a switchgear 'construction wherein the walls of the unit may be made of preformed concrete, or the like, and readily assembled in the field. Where preformed reinforced concrete slabs are used, a single slab may be used between two adjacent units or cells of a switching station.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawings forming a part thereof.

In the drawings:

Fig. 1 is a plan view, in partial section, of a switchgear constructed in accordance with the teachings of the present invention, said view being taken along the line ll of Fig. 2, and looking in the direction of the arrows;

Fig. 2 is an elevational view, in partial section, of said switchgear, said view being taken along the line 2-2 of Fig. 3, and looking in the direction of the arrows;

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2', and looking in the direction of the arrows;

Fig. 4 is a rear view of the switchgear being taken along the line 4-4 of Fig. 2, and looking in the direction of the arrows;

Fig. 51s a front view of the switchgeansaid View being taken along the line 5-5 of Fig. 2, and looking in the direction of the arrows;

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 2, and looking in the direction of the arrows, but with the breaker withdrawn;

Fig. '7 is a view corresponding to Fig. 2 and showing the circuit breaker inits retracted position;

Fig. 8 is a view showing the circuit breaker retracting mechanism in position for inserting or retracting the circuit breaker, said view being taken along the line 8-8 of Fig. 2 and looking in the direction of the arrows;

' Fig. 9 is a sectional view taken along the line 9-9 of Fig. 8, and'looking in the direction of the arrows; 1

Fig. 10 is a sectional view taken along the line Ill-l0 of Fig. 8 and showing the interlocked mechanism in its released position;

Fig. 11 is a view similar to Fig. 10 and showing the interlocking mechanism in its locked position;

Fig. 12 is a sectional view through the vent valve for connecting the exhaust gas conduit from the circuit breaker to avcommon header, said view being taken along the line I2-l2 of Fig. 13;

Fig. 13 is a fragmentary elevational view of the venting connection valve;

Fig. 14 is a sectional view taken along the line |4-ll of Fig. 5 and illustrating the secondary disconnect switch for establishing electrical connections to the control mechanism;

Fig. 15 is a fragmentary sectional view illustrating the manner in which a truck for trans- 3 of one of the plates bus-bar compartment and a portion of the top of the circuit breaker compartment;

Fig. 20 is an elevational View of the plate of Fig. 19;

Fig. 21 is a fragmentary sectional view illustrating an alternate method of supporting the bus-bars in the bus compartment;

Fig. 22 is a plan view illustrating an alternate circuit breaker retracting and inserting mechanism, said view being taken along the line 22-22 of Fig. 23, and looking in the direction of the arrows;

Fig. 23 is a sectional view taken along the line 23-23 of Fig. 22, and looking in the direction of the arrows;

Fig. 24 is a view corresponding to Fig. 2 and illustrating the principles of my invention applied to a switchgear of the type having two sets of bus-bars;

Fig. 25 is a sectional view taken along the line 25-25 of Fig. 24, and looking in the direction of the arrows;

Fig. 26 is a view taken along the line 20-28 of Fig. .24:

Fig. 2'7 is a diagrammatic view illustrating the principles of my invention as applied to a switchgear of the type including a main bus and a transfer bus;

Fig. 28 is a sectional view taken along the line 28-22 of Fig. 29 and illustrating the principles of the present invention as applied to a precast concrete switchgear;

Fig. 29 is a sectional view through the precast concrete type of switchgear, said view being taken along the line corresponding to the section of Fig. 2;

Fig. 30 is an enlarged fragmentary sectional view taken along the line 30-40 of Fig. 29;

Fig. 31 is an enlarged fragmentary sectional view taken along the line il-Il of Fig. 29;

Fig. 32 is a sectional view through the circuit breaker disconnect switch;

Fig. 33 is a sectional view taken along the line 3H3 of F18. 32;

Fig. 34 is a sectional view taken along the line 34-34 of Fig. 32; and

Fig. 35 is a sectional view through the bus-bar disconnecting switch.

Reference may now be had more particularly to Figs. 1 to 14 inclusive. The switchgear here shown comprises a stationary structure having a lower compartment into which a circuit breaker is movable horizontally to establish circuit connections through the circuit breaker. Above the circuit breaker compartment is one or more busbar compartments, and to the rear of the circuit breaker compartment is a compartment for housing the incoming or outgoing circuit conductors or lines, the arrangement being such that the incoming line can extend to, the switch housing from an upwardly or a downwardly direction. A plurality of such units are placed side by side, depending upon the number and kind of circuits at the station, so that the bus-bar compartments of the respective cells are in alignment. Busbars extend through the respective aligned cells in the form of continuous bars running from cell to cell. If desired, insulating barriers may be placed between the bus-bar compartments of adjacent cells, and those barriers may be made to support the bus-bars. The stationary structure comprising the cell of the switchgear of Figs. 1 to '7 inclusive, includes a circuit breaker compartment l, a bus-bar compartment 2, and a current transformer compartment I into which the incoming or outgoing lines are extended. The stationary structure is made mainly of sheet metal, with suitable insulating sheets at the desired places, as will more fully appear as this description proceeds.

The circuit breaker compartment i has two sheet metal sides 6-6 and a sheet metal back II. Each of the sides 6-4 is of a construction such as shown more particularly in Figs. 17 and 18, and comprises a sheet metal plate, the edges of which are turned inwardly to form a flange 1 extending around the entire periphery of the .plate. Angle iron strips I and 8 are welded or otherwise suitably secured to the inner side of each sheet adjacent the top portion thereof. The angle iron strips 8 on opposite side walls 6 of the compartment serve as supports to which is bolted an insulating cover or barrier I I for the circuit breaker compartment, which cover is also the lower wall of the bus-bar compartment 2. The strips 9 on opposite side walls 6 of the compartment serve as supports to which is bolted a plate 12 extending between opposite side walls of the circuit breaker compartment. The plate I 2 carries three circuit breaker disconnecting terminals of a construction such as is shown in Fig. 32, and which will be more fully described as this description proceeds. A steel channel I! is welded or otherwise suitably secured to each side plate 6 adjacent the lower edge thereof, and constitutes a supporting rail for the movable circuit breaker structure, to be more fully described presently. The stop It is welded to the top flange of the channel rail i5 adjacent the rear thereof, to limit the extent of rearward movement of the circuit breaker within the cell.

The rear wall ll of the circuit breaker compartment extends above the top of the side walls of that compartment and constitutes also the rear wall of the bus-bar compartment. The top edge of the rear wall I1 is bent forwardly to form a short flange 20, which flange 20 acts as a support for a cover plate 39 for the bus-bar compartment and as a support for a plate 25 on which is mounted the bus-bar supporting insulators. An angle iron plate 22, of a shape such as is shown more particularly in Figs. 19 and 20, serves to complete the front closure of the bus-. bar compartment. This plate includes a vertical portion 23, and a lower horizontal portion 24, which serves also as a part of the top of the circuit" breaker compartment. The top of the plate 22 has a rearwardly bent flange 25 which corresponds, functionally, to the flange 20 of the back plate II. An additional flat sheet metal cover plate 28 is provided for the upper front portion of the circuit breaker compartment, said sheet metal plate resting on and being welded to the upper peripheral flange of the opposite side walls 6 of the circuit breaker compartment, and being continuous at its lower side with the lower surface of the plate 24. The plate 28 has two holes therethrough adjacent its rear edge, one at each side of the switch housing, which holes receive the pipes for the venting of the circuit breaker and for the control conductors, and also act as a part of an interlocking system, as will be more fully described.

In Figs 1, 3, 4, 5 and 6, I have shown a complete cell with fragmentary portions of adjacent cells of like construction. In the embodiment of the invention illustrated in Figs. 1 through '7, the bus-bar compartment of each cell comprises a. hollowtrough having top, bottom, front and rear walls, but no side walls, so that by placing ad- Jacent cells in abutment with one another, the troughs forming the respective bus-bar compartments are in alignment and constitute one long trough through which the bus-bars extend. There. are three bus-bars, one for each phase, as indicated at 3|, 32 and 33 respectively. The busbars are supported by insulators 34, three such insulators being mounted in alignment upon a plate 35 which is bolted to the flanges and of the rear and front walls, respectively, of the bus-bar compartment. One bus-bar supporting plate, 35, is located at each junction of adjacent switching units. Each bus-bar extends continuously through a plurality of switching units, being supported by clamps 36, (Fig. 3), at the lower end of each insulator. A cover plate 39 is bolted to the flanges 20 and 25 of the rear and front walls of the bus-bar compartment, and extends from one bus-bar supporting plate to the adjacent bus-bar supporting plate 35. The cover plate 39 is removable for inspection or repair purposes, and thus allows ready access to the bus-bar compartment from above.

The insulating plate In which is bolted to the lower flange of the angle strips 8 and extends between the two walls 6 of the circuit breaker compartment, constitutes the bottom of the bus-bar compartment and is removable to permit access to the bus-bar compartment from below.

The rear wall H of the circuit breaker compartment carries three circuit breaker disconnecting switch terminals 45 mounted in horizontal alignment, which terminals include a stationary contact that is adapted to receive a coperating contact carried by the movable structure, which cooperating contact engages the sta- ,tionary contact when the circuit breaker is brought into its proper position in the compartment. The terminal which is mounted on the stationary part of the switch structure, and the cooperating terminal which is mounted on the movable part of the switch structure together form a circuit breaker disconnecting switch, which is illustrated more particularly in Fig. 32, and which will be described more fully as this description proceeds. It is sufiicent here to state that each swltch includes a tube of insulation, 46, in which is mounted a stationary contact finger 41, and that the movable contact structure that is moved into engagement with the contact finger 41 is mounted in such a manner as to permit an appreciable movement thereof in all directions so that the tube 46 may guide the movable contact into proper engagement with the stationary contact 41 even though the structure carrying the movable contact is appreciably out .of alignment with the stationary contact. By

this arrangement the need for extreme precision in aligning the movable circuit breaker structure with the stationary structure is eliminated. Three circuit breaker disconnecting terminals 49, which are of the same construction as the terminals 45, are mounted in horizontally spaced alignment on the plate I2 at the forward part of the circuit breaker compartment. The stationary terminals of these switches are connected by copper bars 50, 5| and 52 to the respective bus-bars 3|, 32 and 33, the Joints between the connecting bars 50, 5| and 52 and busses 3|, 32 and 33, respectively, being made in the field. The stationary contacts of the rear circuit breaker disconnecting terminals are connected by means of conductors 54, 55 and 56, (Fig. 4), to the incoming conductors 51 through suitable current transformers 58. In the .present construction the incoming line conductors extend to the transformer compartment from underground. It is to be noted that the space above the circuit breaker disconnecting terminals 45 is unobstructed. By this arrangement the current transformers 58 may be mounted above the terminals 45 when the line 51 extends into the compartment 3 from above, instead of from below.

A description will now be given of the movable structure that includes the circuitv breaker, from which description it will be seen that the respective circuit breaker disconnecting terminals 45, and the respective disconnecting terminals 49, for the three phases, are spaced apart a distance greater than the spacing between poles of the circuit breaker. By reason of this greater spacing of the disconnecting terminals, it is possible to rely upon air insulation, thus dispensing with the need for insulating the respective conductors 50, 5|, 52 that extend to the bus-bars, and the respective conductors 54, 55, 56 that extend to the current tranformers.

The circuit breaker is illustrated at 10 and includes the usual tank 1| depending from a head 12 from which the bushings I3, I4 and I5, and the bushings 16, TI and I8 (Figs. 2, 3 and 6), extend vertically. This is the usual construction in circuit breakers that are designed for vertical movement in a circuit breaker compartment, as was heretofore the standard practice. The circuit breaker includes a rectangular flange at the juncture between the head and the tank. I propose to mount this circuit breaker in -a movable structure by means of this flange 80'.

rectangular opening at the lower portion thereof to permit the circuit breaker operating mechanism to project therethrough, as may be seen in Fig. 5. The upper front portion of the movable structure terminates somewhat above the insulating barrier 93 at a box-like structure 96 including a bottom 91, a front 98, a top 99, and a rear wall I00 and side walls IUI and I02 (Fig. 6).

these disconnecting contacts III), II I and 2 are spaced apart a greater amount than the spacing between the poles I3, I4 and I5 of the circuit breaker. The spacing of the poles of the circuit breaker is determined by the physical dimensions of the breaker. Where the breaker is made as small as possible, the three poles 13, I4 and 15 are quite close together and must, therefore.

be covered with insulation to provide adequate safety for the voltages encountered. The rear wall 92 of the movable structure necessarily has more space for the conductors of the respective phases, and by utilizing this additional space those conductors can be spaced sufiiciently far apart to eliminate the need 'of insulatingwrappings around the conductors that extend from the circuit breaker disconnecting terminals. This result is accomplished merely by utilizing the additional space available in the wall of the circuit breaker compartment over and above the spacing available in the circuit breaker itself. To accomplish this result, the conductors from the respective poles I3, I4 and I5 oi the circuit breaker are outwardly spread as they extend to the circuit breaker disconnecting contacts III], III and H2. The terminals III), III and H2 are of a construction such as is shown more particularly in Fig. 32, to which reference will be had as this description proceeds.

A set of three circuit breaking disconnecting contacts II5, spaced horizontally from one another, are mounted in the wall I of the movable structure and cooperate with the respective contacts of the switch portion 43 mounted in the wall I2. Insulated conductors II8 extend from the respective poles 16, I1 and I8 to the con tacts II5. These contacts are also of the construction shown in Fig. 32. As may be seen from Figs. 1, 3 and 6, the conductors I I8 of the three phases are spaced from one another at their free or disconnect contact making end by an amount greater than their spacing at the end where they are connected to the poles of the circuit breaker. This additional spacing is possible because the width of the bus-bar compartment is necessarily greater than the width of the circuit breaker. By utilizing the increased width of the bus-bar compartment to space the circuit. breaker disconnecting contacts a greater distance apart, I eliminate the need for applying insulation to the connecting conductor bars 58, 6| and 52 (Fig. 2). It is thus apparent that the present construction utilizes the space which is necessarily available, to obtain maximum clearance dimensions between live parts of different phases and between live parts and ground. The center to center distance between the circuit breaker disconnecting devices is greater than the center to center distance between oil circuit breaker bushings, and the distance between the circuit breaker disconnecting devices and ground is'also greater than the distance between the oil circuit breaker bushings and ground.

It is to be noted that the connections from the bushings 13, II and I of the circuit breaker do not extend through the bottom wall of the busbar compartment. Therefore the space heretofore taken by such connections, in the usual vertically movable structures, is unencumbered thereby permitting ready access to the bus-bar compartment from below.

The movable structure is supported by wheels mounted on the rails I5 of the side walls of the bus-bar compartment. The circuit breaker disconnecting terminals are constructed in such a manner that they have considerable latitude of movement and are guided into proper position by the outwardly flared or tapered open end of the insulating tubes 46 associated with the terminals of the stationary structure, as will be more fully set forth in the description of the switch shown in Fig. 32. This eliminates the necessity for close tolerances in fabrication and assembly of the structures.

The circuit breaker is mounted in the movable structure, and the terminals of the circuit breaker are connected, to the circuit breaker disconnecting contacts of the movable structure by 5 conductors that remain stationary with respect to the circuit breaker as long as the circuit breaker is within the movable structure. By this arrangement, any circuit breaker of the requisite current and voltage characteristics may be mounted within the -movable structure without regard to the particular locations of the circuit breaker bushings. In the prior constructions, wherein the circuit breaker itself carries the disconnecting contacts that engage the contacts carried by the stationary structure, it is not possible to effect a ready replacement of one type of circuit breaker with another. This means that in a large substation employing many circuit breakers they must all be of the same construction, or spare circuit breakers of each design used must be provided. v

An explanation will now be given of the manner of making the secondary control connections to the circuit breaker operating mechanism and of the manner of connecting the circuit breaker venting outlet to a common header or exhaust conduit, for which reference may be had to Figs. 2, 3, 5 and 8 to 14, inclusive. Each circuit/breaker is provided, at one side, with a venting outlet for the escape of gases that are produced during circuit interruption, as is well known in the art. This outlet is shown at I30 in Figs. 2 and 3. A flexible steel pipe or conduit, I3I, is connected to the outlet I30 and extends through an oversized opening I32 in the front wall 94 of the movable circuit breaker supporting structure. The con duit I3I is connected to a vertically movable pipe I33 by means of a T connection I34. The pipe I33 extends through aligned openings in the plates 61, 99 and 28, to a check valve I35 (Fig. 2), that controls communication with an exhaust conduit or header I36 that extends along the front of the bus-bar compartment for the full length of the set of side by side switching units.

The valve I35 is shown more particularly in Figs. 12 and 13, to which reference may be had. The valve includes a T coupling for joining adjacent pipe lengths of the header I38. The coupling has a stem I38 in which projects a short tube I39 that terminates at its top in a disc I40 which constitutes a check valve which normally closes oif communication between the header I36 and the stem I38. When the tube I39 is raised, communication is established between the header I36 and the lower outlet of the stern I38 through slots I in the tube I39. When the pipe I 33 is raised so that its upper end projects through an opening in the plate 28 and into the stem I38 of the valve I35, the pipe I33 raises the tube I38, thus opening the check valve I40 and establishing communication between the pipe I 33 and the common exhaust header I36. Ex haust gases can now flow from the circuit break er, through the connection I 3i, pipe I33, valve I35, to the common exhaust header I36. When the pipe I33 is lowered to disestablish connections between the circuit breaker and the header I 36, the disc I40 of the check valve seats to close the outlet of the stem I38 of the T-shaped check valve I35, while permitting unobstructed flow of gases through the connected portions of the lengths of pipe I36 at the T. The pipe I33 may be lowered until its upper edge is below the top of the plate 28. In order to facilitate raising of the pipe I33, the holes in the plate 28 and in the plates 81 and 99 are oversized to permit the operator to wabble the pipe I33 slightly to pass the top of the pipe through the opening in the plate 28.

Secondary control connections to the circuit breaker operating and control mechanism are made through a secondary disconnecting switch I45 of the plug and socket type, the location of which is shown in Fig. 5, and the construction of which is shown more particularly in Fig. 14. One set of contacts of the switch I45, namely the malecontacts, are carried at the upper end of a pipe I45 which is vertically movable to bring the male contacts into and out of engagement with the cooperating female contacts on the stationary structure. The pipe I46, like the pipe I33, extends through openings in the plate 28 and in the plates 91 and 59, which openings are made oversize in order to permit a limited wabbling of the pipe I46 by the operator to bring themale contacts into registering engagement with the female contacts of the switch, even though the movable circuit breaker carrying structure is not in precision alignment within the stationary structure. The secondary control conductors extend through a flexible conduit to a splicing chamber I47 to which the conductors are extended through pipes in any desired manner. The box I47, which is located at the front of the busbar compartment, supports the control relay which closes the oil circuit breaker control circuit, said relay being mounted on the front wall of said box. The inside of the box I41 serves as a junction box for control wires from the operating solenoid of the oil circuit breaker, control wires from the operating center, tap-01f wires from the direct current control buses, which pass through the box from unit to unit, and for connections to the control relay. Space is available in this box for terminal blocks for any or all of these circuit control wires.

The pipe I33 has a disc I48 welded thereto, and the pipe I46 has a similar disc I49 welded thereto. When these pipes are in their raised position, the disc I48 rests on the right-hand end of a horizontally movable slide bar I50. and the disc I49 rests on the left-hand end of a similar horizontally movable slide bar I5I, as is shown in Fig. 11. These slide bars are supported by depending brackets I53 and I54 that are secured to the wall 91 of the movable circuit breaker supporting structure, and are free to slide through the brackets. The bar I is continuously urged to the right, as seen in Fig. 10, by a tension spring I55 that extends from the bracket I54 to a pin or handle I5I that is secured to the bar I50. In a like manner the bar I5I'is urged to the left, as seen in Fig. 11, by a tension spring I58 that extends from the bracket I53 to a pin or handle I59 secured to the bar I5I. The handles I51 and I55 facilitate manual movement of the bars I50 and till towards one another to bring the ends of those bars from under the discs I48and I49 to permit the pipes I33 and I46 to drop. The bars I50 and I5I each have a channel bend therein, as it may be seen in Fig. 8. The bar I50 has a hole I50 therein, and the bar I5I has a hole I6! therein, which holes are out of register with one another when the bars are in their normal position when the circuit breaker is properly and completely positioned within the bus-bar compartment, as may be seen in Fig. 11. When the handles I5? and I59 of the bars I50 and I5I are moved towards one another to bring the bars out of the paths of movement of the discs H38 and I59, the holes I59 and IGI are brought into reg: ister with one another, as may be seen in Figs. 8 and 10.

When the pipes I33 and I45 are in their raised position, andheld in that position by the bars I50 and I5I, they prevent retraction of the movable structure that carries the circuit breaker. Any attempt to retract the movable structure from the circuit breaker compartment is resisted by the engagement of the pipes I33 and I46 with the plate 28 through which the pipes extend. In order to withdraw the circuit breaker from the circuit breaker compartment, it is necessary first to efiect a lowering of the pipes I33 and I45 to clear the plate 28, which can be done only by first moving the bars I50 and I5I towards one another so that the bars clear the discs I48 and I49. When this is done, the circuit breaker is tripped, as will be presently described.

1 Each of the bars I50 and I5I has an additional hole I53 therein, which holes are brought into alignment with one another when the bars are in their locking position, as illustrated in Fig. 11,

and are out of alignment when either bar is in go a position to permit dropping of its associated pipe I33 or I46. A latch I64 is located on the housing of the circuit breaker tripping mechanism, being mounted on a pin or shaft I85 (Figs. 9 and 11), so that upon turning of the latch I64 the shaft I65, which extends into the housing of the operating mechanism, is turned. When the shaft I55 is in the position illustrated in Fig. 10, a projection on this shaft, within the housing of the operating mechanism engages the tripfree latch of the operating mechanism and prevents closing operation of the circuit breaker operating mechanism, or effects tripping of the mechanism if the mechanism is in its circuit breaker closed position. If the shaft I65 is rotated in a clockwise direction, as seen in Fig. 11, the projection on the shaft clears the tripping latch of the operating mechanism and permits (but does not cause) normal operation of the circuit breaker. The shaft I55 cannot be turned clockwise from the position shown in Fig. 9 unless and until both holes I63 in the bars I50 and I5I are in alignment, at which time such turning is possible, and the portion I56 of the latch enters both aligned holes. Thereafter, in order to move the bars I50 and I5I laterally from the position of Fig. 11, it is necessary first to turn the latch I64 out of engagement with the two aligned holes I63, thus tripping the circuit breaker or, if the circuit breaker is already in its open position, preventing closure thereof. When this has been done, the bars I55 and I5I may be moved laterally to the position shown in Fig. 10. The ends of the bars now clear the flanges I45 and I45 on the pipes I33 and I46 so that the pipes drop by gravity and permit retraction of the circuit breaker.

The pipes I33 and I56 drop until they engage angle stops I58 (Figs. 5and 7) which limit theirv movement to the position illustrated in Fig. 10. At this time the flanges I48 and I49 prevent the bars I58 and I5I from moving back to the position illustrated in Fig. 11, and thus prevent alignment of the two holes I63 in those bars,

thereby preventing manual movement of the latch in a clockwise direction to free the tripping mechanism and permit circuit breaker operation.

In order to move the circuit breaker in its cell, when the interlock has been released as above pointed out, I employ a drawout mechanism, one embodiment ,of which is illustrated in Figs. 8 and 9. This drawout mechanism comprises a cross-bar I III to which are secured tubular collars Ill and I12 through which bolts II3 and I74 with comparatively long shanks, extend.

The bolts I13 and I" are threaded into nuts I15 and I I5, respectively, that are permanently secured to the side walls 6 of adjacent cells, as is indicated in Fig. 8. A screw I18 swivels in the cross-bar I10, being held against longitudinal movement therein, and is provided with a handle I19 for turning the same. The movable circuit breaker carrying mechanism has a bar I80 secured across the front face thereof, which bar is threaded to receive the screw I'IB. Turning of the screw I18 through the threaded hole in the bar I80 threads the screw into the bar. Thereafter the bolts I'I3--I'|l are threaded into the nuts I15 and H5 to secure the drawout mechanism in place. Further turning of the screw I18 causes the screw to draw the circuit breaker supporting structure, with the circuit breaker, outwardly of the cell. On the other hand, if an attempt is made to insert the screw I18 through the bar I80 when the holes I60 and I6I are not in alignment, the screw engages the bar I which prevents further insertion of the screw, thereby preventing retraction of the circuit breaker. Upon turning of the screw I18, when the bars I50 and I5I have been moved to bring the holes I50-I6I into alignment, the circuit breaker is retracted, the wheels 84--84 riding upon the rails I5. A pin I85, having a flange intermediate the ends thereof, is dropped through aligned holes I85 in the flanges of the rail I5 so that the upward projecting portion of the pin limits the outward movement of the circuit breaker on the rails. The retracting mechanism may be removed by merely unthreading the bolts I13 and I14 and then unscrewing the screw II8 from engagement with the threaded hole in the bar I80. If this is done after the bolts ITS-I'll have been turned out of engagement II5-I'I5, such turning of the screw does not force the circuit breaker into its cell, as is apparent from the construction previously described.

If it is desired to remove the circuit breaker from the cell, a truck having spaced rails I5-I 5', (Fig. 15), is brought adjacent the cell so that the rails on the truck match with the rails I5 on the side wall 6 of the bus-bar compartment.

' Each of the channel-shaped rails I5 has a short channel I welded on the inside thereof and projecting forwardly thereof, as is illustrated in Figs. 15 and 16. When the rails of the truck are brought into engagement with the rails on the circuit breaker compartment, the forward projecting portions of the channels I90 enter the troughs of the channels I5 with the webs of the channels I90 bearing against the webs of the channels I5. .The flanges oi the channels I90 have holes I9I therein which register with the holes I86 so that a pin I92 may be dropped through the holes I85 and through the holes I9I of each pair of rails to lock the truck to the rails I5. The holes I86 are countersunk so that the head of the pin I92 is flush with the top surface of the flange of the rail I5. The circuit breaker may now be removed from the rails I5 to the rails I5 of the truck, after which the pins I92 may be removed to release the truck. The truck with the circuit breaker thereon can then be moved to any desired place.

a When the circuit breaker has been taken out of the circuit breaker compartment, the insulating plate or barrier I0 may be removed to allow access to the bus-bar compartment from below the same. From the above description, it is apparent that the switchgear of the present invention is exceedingly simple and economical of construction since no extremely accurate alignment of parts is necessary, and it does not require extensive manutacturing equipment for its fabrication. The circuit breaker used is a standard circuit breaker of the type heretofore used in switchgear of the kind where the circuit breaker is brought into its operating position by a vertical upward movement. The only change wrought in the circuit breaker is that the standard circuit breaker disconnecting contacts have been removed. The movable structure 8I comprises an adapter for adapting a standard vertical lift or other type of circuit breaker for use in the present switchgear. Furthermore, since the circuit breaker, which constitutes the heaviest part of the switchgear, is supported adjacent the bottom of the circuit breaker compartment, I eliminate the need for heavy structural steel members for supporting the busbar compartment or for reinforcing the circuit breaker compartment. Since all contacts are enclosed, the side walls 6 or each cell may be replaced by an open framework supporting the bus-bars and providing a support for the rails I 5. Also, the wheels on the movable circuit breaker supporting structure may be located appreciably 35 lower than they are, as shown in Fig. 2, so that the wheels ride upon rails at the ground level.

In the event that the circuit breaker is of the type having its own supporting wheels, as in my pending application, Serial Number 97,541, the Q0 entire structure 8| may be dispensed with and the box 95 with its pipes and associated interlocking mechanism can be secured directly to the circuit reaker, the circuit breaker disconnects being then supported entirely by the circuit breaker.

Reference may now be had more particularly to Fig. 21 where I show an alternate method of supporting the bus-bars. In this construction the bus-bars are supported by insulating barriers 200, in the form of plates, that extend vertically between the bus-bar compartments of adjacent cells and thus close off the bus-bar compartment of each cell. Each one of the insulating barriers 200 is provided with three holes, one for each busbar, which holes may have porcelain or other insulating bushings 20I inserted therethrough, and through each one of which a bus-bar extends. The barriers 200 rest upon the top of the side walls 6-45 or" adjacent units, and each barrier extends from the front of the bus-bar compartment to the rear wall I thereof.

In 22 and 23, I have shown an alternate circuit breaker retracting mechanism. This mechansim differs from that of Figs. 8 and 9 primarily in the manner whereby it is supported. The mechanism includes a pair of vertically extending legs 2 I02 I 0 which are bent horizontally at their top to form arms 2I I-2I I and joined by a cross-bar 2 I 2, the vertical legs 2 I 0, the arms 2I I and the bar 2I2 comprising one integral metal member formed into the shape shown. The arms 2 I 0 are adapted to be placed in abutment with the side walls Ii of the circuit breaker compartment and are provided with a bifurcated latch 2 I that embraces the side walls and is releasably held in place by a pin 2I5 in the side wall of the switchcell. When the retracting mechanism is in this position, it cannot be moved with respect to the circuit breaker compartment. The bar 2 I 2 corre- Reference may now be had more particularly to Figs. 24, 25 and 26 wherein I have shown the principles of the present invention applied to a switching unit, including two bus compartments, as fora double bus. The switching unit 222 includes the circuit breaker compartment 22!, one bus compartment 222, another bus compartment at 223 and a current transformer and connecting compartment at 22 3. The circuit breaker compartment includes side .wall 6, of a construction such as was previously described, except that the angles 8 and 9 (of Fig. 17) are omitted. In this construction the circuit breaker is mounted in a movable structure similar to that previously described, except that the two circuit breaker disconnecting contacts, which are carried by the movable structure, are both located at the rear wall of the movable structure in two horizontal rows one above the other instead of having one set advanced forward of the other, as in Fig. 2. The interlocking arrangement, venting arrangement, and circuit breaker pull-out arrangement in this construction are the same as in the construction previously described. The rear wall 22! of the switchgear has two sets of circuit breaker disconnecting contacts which cooperate with corresponding contacts 230 mounted on the ends of insulated conductors 23! carried by the movable structure and extending to the respective terminals of the circuit breaker. Each of the circuit breaker disconnect switches 228 and 229 is of a construction such as is shown more particularly in Fig. 32, which will be described more fully as this description proceeds. There are three switches 228 and three switches 229, one switch in each set being provided for each phase, since the circuit breaker is a three-phase breaker, and they are spaced apart a greater distance than the center to center distance between the circuit breaker bushings, as in the structure of Fig. 2,

to allow the use of bare conductors for extending the circuit to and from those switches. The wall 222i terminates at the top of the circuit breaker compartment, which compartment is closed by an insulating plate 232 that is bolted in place. A wall 236, which comprises the rear wall of the main bus-bar compartment is flush with the wall 227 and carries three disconnecting or bus-bar selector switches 235, one for each phase, in horizontal alignment. The switches 235 are of a construction such as is shown more particularly Fig. 35 and will be more fully described as this description proceeds. It is suflicient to state, for the present, that each switch 235 comprises a tubular insulating structure 236 mounted on the rear wall 232 and provided with a stationary con tact finger 222 which is adapted to receive a movable contact 238 that is horizontally slidable within the tube 236, being actuated by means of an insulating rod 240. The movable contact 238 of each switch is connected, within the switch, to a switch terminal 24!, the terminals of the respective switches being connected to the respective bus-bars in the compartment 222.

The upper bus compartment 223 includes a rear wall 2:35 which supports three switches 2 35, in horizontal alignment, each of the switches being of the same construction as the switch 235. The terminals 26? of the respective switches 2% are connected to the respective bus-bars of the bus in this compartment. f

Each of the switch rods 2% is actuated by a linirv 2 32 connected to a common shaft 263 which is turned by a handle 2% to actuate all three switches 235 in unison. Each switch 246 is operated by an insulating pull rod 250, each pull rod being connected by a link 25! to a common shaft 252 which is turned by means of a link 253, a pull rod 254 and a handle'255 pivoted at 256.

A narrow metal plate 260, of a width corresponding to the width of the plate 35 of Fig. 1 supports three insulators at its lower side for carrying the lower bus-bars and it also supports three insulators at its upper side for carrying the upper bus-bars. These plates 26!! are provided at the juncture between each pair of switchgear, in the manner illustrated in Figs. 1 and 26, and the space between the plates is closed ofi by another plate 26! corresponding to the plate 39 of Fig. 1.

The stationary terminals of the switches 228, 235 and 256 for each phase are connected together by conducting bars 266. The stationary terminals of the circuit breaker disconnecting switches 229 are connected by conductors 265, through current transformers 256, to the respective incoming or outgoing lines 267. The control conductors for controlling the operation of the circuit breaker, and for giving the various signalling indications of the operated or non-operated condition of the circuit breaker, are extended to the switchgear by way of a conduit 2') that passes through the compartment 225, thence across the switchgear through a conduit 21! and downwardly through a. conduit 2'i2 to a juncture box 2T3.

From the above description it is apparent that the line conductors 261 may be connected through the circuit breaker to either or both buses, and that the buses may be interconnected, by means of the selector switches 225 and-246 independently of the circuit breaker.

In Fig. 27, I have illustrated, diagrammatically, a. switchgear which is adapted to establish connections between an incoming or outgoing line and either a main or a transfer bus; that is, through a circuit breaker to the main bus or through a selector switch to the transfer bus. The bus compartment of this switchgear is indicated at 280 and is of a. construction exactly like that of the switchgear illustrated in Fig. 2. A main bus compartment 22! is located above the circuit breaker compartment, being of a construction identical with the bus compartment of Fig. 2. A transfer bus compartment 282 is located above the bus compartment 28!. bus compartment 282 are connected to the respective ones of three horizontally aligned selector switches 282 of a construction such as is shown in Fig. 35, and in the same manner as the bus-bars are connected to the switches 2% of Fig. 24. The three switches 283 are operated in exactly the same manner as are the switches 2% of Fig. 24, previously described. The incoming or outgoing line conductors are connected, through a current transformer, to the circuit breaker disconnecting contacts 285 in the same manner as in Fig. 2. In addition, the stationary terminals of the switches 283 and 285, of corresponding phases, are connected together by fiat conductors 286 corresponding to the conductors 266 of Fig. 24.

It is apparent from the above description that the line may be connected to the main bus within the compartment 28! through the circuit breaker, or it may be connected to the transfer bus within the compartment 282 through selector switches 223 independently of the circuit breaker.

Reference may now be had to Figs. 28 to 31 The bus-bars of the inclusive, wherein I illustrate the principles of the present invention as applied to a switchgear wherein the major parts of the stationary housing structure are formed of pre-cast concrete slabs, which slabs may readily be assembled in the field. The shape of this type of switchgear is'exactly the same as that previously described in connection with Fig; 2, and the further description thereof ls'not necessary at this time, except for the fact that where concrete slabs are used for the side walls of the switchgear, a single slab serves as the dividing wall between two adJacent units, rather than two separate walls. The walls 333, 3", 302 and 333 comprise pre-cast, concrete slabs.: Each side wall is reinforced by an inwardly facing channel-shaped iron or steel rim 303 which extends around the entire periphery of the wall. In the casting of the wall, the rim 333 constitutes a part of the mold. Suitable metal tubes or thimbles 303 are placed in the mold at'the proper places where it is desired to have holes extend through the concrete slab for the reception of bolts tosecure parts to the slab or to secure adjacent slabs together. The rails ll aresecured to. opposite side walls 333 by bolts 303 that pass through inserts 304 in the concrete wall and securethe rails in place, as is illustrated in Figs. 29 and 31. The angle members 3 and 3 are secured to the side wall 333 by bolts 3|. that extend through thimbles in the concrete at the proper places, said bolts securing the angle members in the same manner as the bolts secure the channels, as illustrated in Fig. 31. The stationary parts of the three disconnecting switches 43 and of the three disconnecting switches 43 are secured to the respective concrete walls 333 and "I by bolts passing through threaded thimbles which are embedded in the concrete at the proper places during the manufacture of the concrete walls.- The side and rear walls of the structure are secured together by angle clips 3" and bolts 3i4 that extend through tubular inserts at properly located places in the concrete walls, which inserts are located in the concrete during the process of forming the same. The rear wall 332 and the side walls of the current transformer compartment are connected together in the same manner. While I have shown the front wall of the bus-bar compartment as formed of sheet metal in the, same manner as in Fig. 2, this wall may also be formed of pre-cast concrete in the same manner as are the other concrete walls. By forming the concrete slabs with a channel-shaped metal rim, I provide adequate reinforcement, and this rim also facilitates the casting operation. All of the holes for the securing bolts, as well as the holes through which the circuit breaker disconnecting switches extend, are formed during the molding and casting operation of the concrete slabs, thus greatly reducing the cost of installation.

Reference may now be had more particularly to Figs. 32, 33 and 34 which show the construction of the circuit breaker disconnecting switches. As previously stated, the switch comprises a stationary contact 41 mounted within an insulating tube 43 that is secured to the rear wall ll of the switchgear. The tube is secured in place by a split metal ring 33I-332 which is bolted to the wall i1 and tightly embraces the tube 43, thus firmly holding the same in place. The movable contact structureis mounted at the end of an insulated conductor 334 that isf'encased in insulation 335 and suitably secured to the wall of the movable circuit .breaker supporting structure.

The movable contact H0 comprises a copper tube 333 slitted longitudinally in a number of places 331 to form a plurality of fingers, in this instance eight in number, 333. The fingers are outwardly flared at their forward end to guide the same over the tapered forward portion of the contact finger 41 and are pressed towards one another into firm pressure contact with the finger 41 by a plurality of coiled springs 340 which surround the eight contact fingers 333 adjacent their outer end. The copper tube 333 is threaded into a circular plate 3 which in turn is threaded into a collar 342. The collar 342 floats about the center of the conductor 334, being held by four raiially extending coiled springs 344 that extend from the collar 342 to a ring 345 that embraces a stud 343 threaded into a retaining copper tip 341 that is mounted at the end of the :onductor 334. The springs 344 retain the collar 342, and therefore the contact fingers 333 centered with respect to the center line of the conductor 334, while permitting lateral movement of the contact making structure H0 with respect to the conductor 334. A disc 348, threaded into the collar 342 and having an opening appreciably larger than the diameter of the stud 34G, limits the extent of lateral movement of the collar 342 with respect to the center line of the conductor 334 to an amount, in this instance, approximately in each direction. A disc 349, threaded to the forward end of the stud 346, prevents escape of the collar 342 from the conductor 334. A plu rality of flexible jumpers 3H, in this instance eight'in number, are welded at one end to the ring 342 and at their other end to the copper tip 34'! whereby current is carried from the con- .ductor 334 to the ring 342 and thence to the contact making member H3 without any sliding connections.

When the movable structure is away from the stationary structure, that is, the contact making member ilil'is outside of the insulating tube 43, the tube 342 is centered on its support by the springs 344. If, on approaching tube 46 on the stationary structure, the conductor 334 is not concentric with the tube 46, the conducting ring 342 is guided by the insulating tube 46 out of concentricity with its supporting conductor 334 and into concentricity with the conducting stud or finger 41 in the insulating tube. It will be noted that the point of application of the forces which tend to center the conducting ring 342 in the insulating tube 46 are so located that they set up a true sliding action and hence the frictional resistances between the sliding surfaces are much less than they would be if the centering forces were applied against the fingers of the contacting tube 338 by the stud 41 within the insulating tube. Not until the movable structure is practically centered within the tube 46 does the stud or contact making finger 41 take over and complete the guiding function. Thus even if the contact making member of the movable structure is out of alignment with the contact stud in the stationary structure by as much as plus or minus in this particular construction, perfect contact is made.

The selector switches 235 of Figure 24 may be of any preferred construction, preferably of the type wherein the contact making member moves in a straight line within an enclosing tube of insulation. One suitable switch is shown in Figure 18 of my pending application above referred to. Another suitable switch is shown in Figure 35 hereof. This switch comprises an insulating tube 363 which extends through the metal wall 234 of 

